Pass Key Fault Fix
By Mike Lukens
I recently had the opportunity to troubleshoot a Pass Key Fault problem. The Pass Key Fault light would continue blinking and the car would not start. The fuel pump would run for about 3 seconds then shut off but the starter would never try to turn over.
After consulting with all the Impala digests using GREP for Windows and talking to our very own Master Mechanic (who will remain nameless lest he get unwanted calls), we determined that we had a break in the wire in the steering column for the Pass Key circuit. I found the connector under the dash. It is a 2-wire connector with Purple/White and White/Black wires on one side and two white wires on the other side. The white wires go up into the steering column. I checked for continuity on those two white wires with the key in the ignition and found an open circuit. I had previously checked the key and found about 900 ohms…..so I should have had close to that with the key inserted in the ignition switch.
I went to the web to find a parallel circuit calculator so I could make a resistor pack equal to about 900 ohms. (That site is http://www.1728.com/resistrs.htm.) I input 10000 ohms and 1000 ohms and got 909 ohms……close enough. Then I went to Radio Shack and bought packs of 10000 and 1000 ohm resistors. I wanted ¼ watt for both but they were out of the ¼ watt 10000 ohm resistor……but that’s ok..I got the ½ watt…..won’t make any difference.
You can see the parallel circuit I made in the photo below. Not very pretty but it got the job done.
I then plugged that assembly into the connector with the white wires and reconnected the connector. Now when the key is turned to Start, the Pass Key Fault light does NOT blink and it goes out after about 5 seconds……AND the car starts!!! So now we can DRIVE the car to the dealer rather than having it flatbeded over there!!!
For those of you with this problem, the key is to find out what the resistance is of YOUR ignition key. Then check for a complete circuit (continuity) of the pass key circuit. We drove the car to the dealer and they replaced the Ignition Switch cylinder. We had to get new keys made….one at the dealer for $28 and one at Ace Hardware for $18!!!
Here is a photo of the defective part.
I don’t know how this will show up in the black and white copied version but note that there should be TWO wires coming out of the key cylinder…..there is only ONE. The black part rotates every time you turn the key and the wires flex every time you turn the key…..so …..sooner or later every one of us will have this problem!! Note also that the wires are white and encased in an orange covering terminating at the black connector. The cost to fix this was $311!!! Surely our Impala gurus can come up with a cheaper fix!! Sure we could just disable the Pass Key circuit but I think most of us would rather have the circuit working correctly.
Be aware that this problem WILL leave you stranded!!……there is NO recovery from it and NO magic incantation that will get you going again. The Pass Key system is looking for a particular resistance in your key and will not start if it does not see it. I am going to make a jumper for my car with the proper resistance so that WHEN my wires break I can just plug it in an GO…..uuummmmm …..maybe someone could make up some of those jumpers and sell them to us?? Any takers?
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